The owner's manual should show a diagram of the underhood fuse and relay box, identifying each relay. A wiring diagram will be even more helpful; it should show the relay's location and its circuit path. You can find wiring diagrams online through sites specializing in car repair information (like Haynes or Chilton manuals online), or at a parts store.
Without visual reference materials, pinpointing the exact location is impossible. Be prepared to carefully examine the fuse/relay box, checking markings on each relay. Some relays may be unlabeled, requiring a process of elimination using your wiring diagram.
